The invention relates to cargo delivery vehicles. More particularly, the invention relates to cargo delivery vehicles having multiple tiers of cargo storage which can be easily accessed for loading purposes through the rear doors, and can be unloaded through side access doors without requiring total bodily entry into the delivery vehicle in order to retrieve any portion of the cargo.
It is desirable to store and transport a wide variety of cargo in vehicles having multiple storage tiers so that the most efficient use of the interior space in the vehicle can be made. In many distribution industries, single tier delivery vehicles suffer from several disadvantages resulting in the inability to utilize the full vertical capacity of the cargo area. One such disadvantage is that stacking cargo to excessive heights introduces potential payload instability. A second disadvantage is that excessive stacking often results in cumbersome access for manual unloading. A third disadvantage of excessive cargo stacking is that upper cargo may crush lower cargo.
It is also desirable in many distribution applications to utilize a delivery vehicle engineered to produce the structural versatility to both (1) accept palletized cargo through rear doors, as from a warehouse dock, and (2) permit total and random side access to cargo at multiple delivery stops without the inefficiencies or hazards associated with unloading personnel being required to enter the vehicle in order to effect total cargo retrieval.
Typically, the feature of rear loading and random-access side unloading are mutually exclusive in the known art of enclosed delivery vehicle construction. Some delivery vehicles in the food service industry provide rear loading with only limited side access, thus requiring total bodily entry to the vehicle in order to fully unload. This arrangement may achieve advantageous loading capabilities, yet suffer from unloading inefficiencies. Conversely, delivery vehicles common to the beverage distribution industry often permit total exterior access to the cargo areas through multiple side doors for unloading, but they are structurally unsuitable for rear loading.
It is still further desirable to provide an elevating means for raising and lowering cargo such that both an upper and lower tier may be loaded or unloaded from the lower level. Total exterior access to all cargo may be preferably achieved via side doors permitting access to multiple sections of the lower level. The elevating means may then provide the capability to lower upper tier cargo to the side-accessible lower level for retrieval.
Multi-tier storage of cargo is well known in the art. For example, it is known to provide upper and lower fixed storage platforms in a multi-tier cargo storage vehicle, as described in U.S. Pat. No. 4,139,109 issued Feb. 13, 1989 to Murphy. A single rear elevator apparatus used to vertically transfer cargo between fixed tiers, as disclosed in the patent to Murphy, possesses the disadvantage that a fixed upper tier cargo platform may prohibit loading personnel from entering the rear of the vehicle to facilitate the forward conveyance of cargo through the interior of the vehicle. Likewise, cargo vehicles with fixed tiers can not provide random access to all tiers of cargo through side access doors positioned at the lowermost tier.
A variety of specialized interior elevator arrangements have been developed to overcome the disadvantages of exterior lift mechanisms and fixed tiers for multi-tier storage. For example, U.S. Pat. No. 2,832,636 issued Apr. 29, 1958 to Black, discloses the use of a single interior elevator platform extending the length of the cargo storage space, which enables the transportation of cargo in two tiers. Segmented platforms formed by multiple adjoining elevators have also been proposed such as in U.S. Pat. No. 4,701,086 issued Oct. 20, 1987 to Thorndyke. These segmented platforms provide two-tier storage in certain segments and single-tier storage in other segments where tall cargo is to stored. A similar segmented platform lift apparatus in a multi-tier double drop trailer has been disclosed in U.S. Pat. No. 5,092,721 issued Mar. 3, 1992 to Prince.
But these vehicles with interior elevators are structurally limited to receiving and delivering cargo through rear doors only. As in the arrangement shown by Murphy, the forward cargo is inaccessible while the aft cargo is in place. Such an arrangement may provide a spatially efficient means of transporting cargo between destinations; however, they may be ill-suited for adaptation to delivery applications in which cargo retrieval efficiency is a primary concern. Modern distribution systems frequently require the transportation of cargo from a warehouse to multiple delivery stops where unloading efficiency can be greatly enhanced by direct and random access to the entire lower tier through a series of side doors and where an elevating means can also sequentially position individual upper tier cargo platforms at the lower tier level.
A further disadvantage of the vehicles disclosed by Black, Thorndyke, and Prince is that they have elevating cargo platforms that extend transversely the full width of the vehicles"" interior. Although full-width elevating platforms can thereby accept cargo up to eight feet wide, it may be more desirable for cargo portions to be longitudinally divided and independently accessible such that cargo placed within a lower tier cargo portion must reside within the average workman""s arm""s reach, so that his body may remain substantially outside of the delivery vehicle. Accordingly, a half-width elevating means may reduce the workman""s susceptibility to fatigue and injury, since he need not bodily enter the vehicle to load or unload cargo.
In conventional enclosed delivery vehicles having single-tier or multi-tier storage, the floor is typically required to bear the weight of the cargo and transfer those forces transversely through the floor and longitudinally through the side wall members to the vehicle""s axles. The requirement for numerous, closely spaced structural members in the side walls may limit the availability of sizable doors for cargo access from the side of the vehicle. Some conventional vehicles offer limited side access through doors penetrating the side walls, but the structural integrity of such vehicles may be drastically reduced. Therefore, it is desirable to minimize the load-bearing requirements of the side wall of the delivery vehicle in order to afford virtually continuous side access to the cargo.
Moreover, in the construction of enclosed delivery vehicles, the load-bearing floor is typically required to be quite thick for adequate structural support, thereby decreasing the interior space for storage. Therefore, it is also desirable to minimize the load-bearing requirements of the floor of the delivery vehicle in order maximize interior storage space, especially space located in the ergonomically advantageous lower zone of the truck or trailer.
Other problems and disadvantages of prior art systems can be appreciated by one skilled in the art after examination of such prior art and in view of the present disclosure.
The shortcomings of the prior art create a need for an enclosed, multi-tier delivery vehicle in which all tiers can be loaded and unloaded from the lowermost tier. Other shortcomings of the prior art create a need for a multi-tier delivery vehicle that provides multiple side access ports through which the entirety of the cargo can be manually unloaded without requiring unloading personnel to bodily enter the vehicle, or that permits direct and simultaneous exterior access to cargo located at the lowermost tier, or that can be loaded completely through rear doors of the vehicle and unloaded completely through side doors of the vehicle. A multi-tier delivery vehicle providing. one or more of such features may allow the vehicle to carry a double cargo payload. The structure of the upper tier cargo platform keeps the weight of the upper cargo from damaging crushable lower cargo, thus allowing a delivery vehicle to minimize its wheelbase and turning radius by carrying an increased payload capacity in weight per unit of area.
Further advantages over the prior art may be obtained by providing a multi-tier delivery vehicle with a low floor height so that the contents of the delivery vehicle are within arm""s reach of the average delivery worker on the ground, yet providing means to elevate the tiers to the standard dock loading or unloading height.
Still further advantages over the prior art may be obtained by providing an enclosed, multi-tier delivery vehicle in which the cargo storage area is longitudinally bisected in order that cargo portions may remain within arm""s reach of a side wall access door. The cargo portions may be bisected by structures selected to reduce the load-bearing requirements of the side walls and floors, thus permitting greater side access to cargo and minimizing the vertical height of the floor. The bisecting structure may also be enhanced to provide a heat exchange cavity to circulate air between warm and cool zones, and thereby independently regulate the temperature of different cargo bays within the delivery vehicle.
Even further benefits may be obtained by eliminating the structural flooring of the multiple tiers and replacing it instead with shelves for suspending the pallets of cargo above a lower tier. Depending on the elevator position, full-floor platforms can interfere with loading and unloading by forcing persons entering the lower tier of the delivery vehicle to stoop to avoid the platform floor of the second tier. In delivery vehicles with a plurality of elevators, uneven flooring will result if the forward elevators are raised while the rear elevators remain in the lower position. Eliminating such flooring provides a continuous walkway regardless of the elevator position.
It is also advantageous that any elevating means incorporated into a delivery vehicle be redundantly safe to operate, compact to install in the delivery vehicle, and capable of mechanically locking the cargo in position during travel and unloading.
Additional benefits may be found by using one or more compact sliding rear doors, opposed to conventional swing-out or roll-up style doors, saving space, weight, and the inconvenience of opening doors prior to approaching a delivery dock.
Different aspects of the present invention provide improved loading and unloading capability for cargo delivery vehicles by addressing the deficiencies of, and providing the aforementioned advantages and benefits over, the prior art.
According to one aspect of the invention there is provided an enclosed transport vehicle having at least an upper and lower tier in vertical alignment for cargo storage. An upper tier may be lowered with an elevating system in order to facilitate loading or unloading of cargo.
According to a second aspect of the invention, there is provided an enclosed transport vehicle having a plurality of independently operable elevating systems of the type described and having an interior cargo storage area which is longitudinally bisected by a center structural wall such that the elevated cargo adjoins other elevated cargo transversely across said center wall and at least one other elevated cargo in a longitudinal direction.
According to a third aspect of the invention, there is provided an enclosed transport vehicle having a plurality of adjoining elevating cargo systems and being structurally adapted to accept cargo loaded through rear access doors while also permitting simultaneous exterior access to cargo unloaded through a plurality of side access doors.
According to a fourth aspect of the invention, there is provided a lifting mechanism comprising a plurality of pallet-support shelves powered by hydraulic cylinders.
According to a fifth aspect of the invention, there is provided a mechanism to stop the pallet from falling should a failure occur in the hydraulic system.
According to a sixth aspect of the invention, there is provided a special pallet for loading onto the pallet support shelves, the pallet having rollers mounted on the four corners of the pallet to expedite the movement of the pallet down the aisle of the truck. Also provided are dead bolts integral to the pallet that may be bolted through the apertures in the pallet support shelf and into the side and center walls of the delivery vehicle to lock the pallet into place.
According to a seventh aspect of the invention, there is provided an enclosed transport vehicle having a plurality of adjoining elevating systems and multiple side access ports which can be entirely and manually unloaded through the sides without requiring personnel to completely enter the vehicle""s interior in order to retrieve any portion of the cargo.
According to an eighth aspect of the invention, there is provided an enclosed transport vehicle having a plurality of adjoining elevating systems in which the load-bearing requirements of the side walls are substantially shifted to a longitudinally bisecting center wall.
According to a ninth aspect of the invention, there is provided an enclosed transport vehicle having a plurality of adjoining elevating systems in which the load-bearing requirements of the elevated cargo suspended from the outboard roof structure are substantially shifted to diagonal support beams which carry these outboard loads inward to the center structural wall.
According to a tenth aspect of the invention, there is provided a cooling system for and a heat transfer system between the cargo bays created by a longitudinally bisecting center wall.
According to an eleventh aspect of the invention, there is provided a means to raise the transport vehicle""s floor to that of regular loading dock height.
According to a twelfth aspect of the invention, there is provided a compact set of vertically sliding rear-access doors.